Use of a fuel additive in diesel fuel for reducing fuel consumption in a diesel engine

ABSTRACT

The present invention relates to the use of a diesel fuel additive comprising peroxide for reducing the fuel consumption in a diesel engine.

The present invention relates to the use of a diesel fuel additive, comprising a peroxide for reducing fuel consumption in a diesel engine.

Combustion engines, in particular diesel engines, are important in various fields for generating energy. Due to their high robustness and durability as well as their excellent operating performance, they are essential energy sources for example in power generators, agricultural and construction machines, drilling rigs, buses, trucks, trains and ships. Combustion engines produce energy from fuels, so that their operational costs are influenced by the fuel price as well as the fuel consumption.

It is desired to reduce the fuel consumption in an engine inter alia to reduce operational costs. Reduction of the fuel consumption in an engine means that for the same energy provided by the engine less fuel is required. Consequently, an internal combustion engine with reduced fuel consumption provides energy over a longer period of time compared to the same internal combustion engine without reduced fuel consumption. Hence, with the same amount of fuel an internal combustion engine with reduced fuel consumption provides more energy compared to an internal combustion engine with normal fuel consumption.

The published patent application EP 2 780 435 A1 describes the use of TBHP as fuel additive for reducing carbon monoxide and/or hydrocarbon emission as well as increasing the cetane number.

It was an object of the present invention to achieve a reduction of the fuel consumption in diesel engines.

This object is solved with a fuel additive for diesel fuels comprising a peroxide, particularly tert-butyl hydroperoxide (TBHP).

The invention therefore relates to the use of a fuel additive comprising a peroxide in a diesel fuel for reducing the fuel consumption in a diesel engine.

Surprisingly, it has been found that by using peroxides, wherein TBHP is particularly preferred, a reduction of the consumption of diesel fuel in diesel engines is effected.

The use of a peroxide-containing fuel additive particularly provides a reduction of diesel fuel consumption by at least 5%, more preferably by at least 7%, yet more preferably by at least 10%, even more preferably by at least 13% compared to a similar diesel fuel without fuel additive.

This is impressively demonstrated in extensive comparative tests and long-term measurements in Examples 1-5 and FIGS. 1-2 of this application.

A fuel additive is a composition added to a fuel, preferably in amounts of 0.001 to 50 wt. %, more preferably between 0.01 to 25 wt. %, more preferably between 0.1 to 10 wt. % related to the total weight of the fuel. Even more preferably, the fuel additive is added to a fuel in an amount of 0.1 to 1 wt. % related to the total weight of the fuel. By adding a fuel additive to the fuel, the fuel additive and the fuel preferably form a solution.

The fuel additive to be used according to the invention comprises a peroxide, particularly an organic peroxide and preferably TBHP.

In general various organic peroxides can be used as fuel additives. A preferred embodiment is the use of a fuel additive comprising at least one hydroperoxide, dialkylperoxide, cyclic or acyclic ketone peroxide or/and perketal. Further preferred is the use of a fuel additive comprising at least one hydroperoxide, dialkylperoxide or/and a cyclic or acyclic ketone peroxide. Particularly preferred is the use of a fuel additive comprising at least one hydroperoxide and/or dialkylperoxide. Also particularly preferred is the use of a fuel additive comprising at least one perketal.

Hydroperoxides, in particular alkyl-, acyl- or/and arylhydroperoxides, have the general structural formula R—O—O—H.

Dialkylperoxides, in particular cyclic and acyclic dialkylperoxides, have the general structural formula R¹—O—O—R². In cyclic dialkylperoxides the residues R¹ and R² together form a 4 to 10 membered cycle, more preferably a 5 to 7 membered cycle.

Cyclic ketone peroxides have the general structural formula (R¹R²C(—O—O—))_(n), wherein n can be an integer from 2 to 6, the peroxidic bond is formed between the C-atoms to form a cycle, and R¹ and R² represent identical or different organic residues.

Acyclic ketone peroxides have the general structural formula R¹R²C(—O—O—H)—O—O—C(—O—O—H)R³R⁴, wherein R¹, R², R³ and R⁴ represent identical or different organic residues.

Perketals have the general structure R—O—O—R¹—O—O—R, wherein R and R¹ represent identical or different organic residues.

The residues R, R¹, R², R³ and R⁴ represent each independently an organic residue, in particular a hydrocarbon residue which can be substituted with 1 to 3 heteroatoms.

In particular, the residues R, R¹, R², R³ and R⁴ represent each independently

-   -   acyclic linear chain alkyl, preferably having 1 to 20,         preferably 3 to 10 carbon atoms and can be unsubstituted or         substituted with at least one —OMe, —OH, aryl or/and heteroaryl;     -   acyclic branched chain alkyl, preferably having 1 to 20,         preferably 3 to 10 carbon atoms and can be unsubstituted or         substituted with at least one —OMe, —OH, aryl or/and heteroaryl;     -   acyl, wherein acyl represents a moiety having the structural         formula RC(O)—;     -   aryl, wherein aryl is an aromatic moiety with 6 to 10 carbon         atoms, which can be unsubstituted or substituted with —OMe         or/and —OH;     -   heteroaryl, wherein heteroaryl is an aromatic moiety with 4 to         10 carbon atoms comprising one or more heteroatoms, particularly         nitrogen or/and oxygen in the aromatic system, and can be         unsubstituted or substituted with —OMe or/and —OH; or     -   cyclic alkyl, preferably having 3 to 10, more preferably 5 to 8         carbon atoms forming a cycle and can be unsubstituted or         substituted with a least one —OMe, —OH, acyclic linear chain         alkyl or/and acyclic branched chain alkyl.

In a preferred embodiment the fuel additive comprises tert-butylhydroperoxide (TBHP), cumene hydroperoxide, methylethyl ketone peroxide, in particular cyclic or acyclic methylethyl ketone peroxide, acetone peroxide, tert-amyl hydroperoxide (TAHP), di-tert-butyl peroxide (DTBP), tert-butyl peroxybenzoate (TBPB), 1,1-Di-(tert-butylperoxy)-cyclohexane (CH), tetramethyl-dioxa-cyclohexane (TMDOCH) or 1,1-bis-(tert-butylperoxy)-3,3,5-trimethylcyclohexane (TMCH), 1,1-bis-(tert-amylperoxy)-cyclohexane, 2,2-di-(tert-butylperoxy)-butane (BH), ethyl-3,3-di-(tert-butylperoxy)-butanoate (EBU) or 4,4-bis-(tert-butylperoxy)-valeric acid-n-butyl ester (NBV) or mixtures thereof.

Specifically when using a fuel additive comprising hydroperoxide, dialkylperoxide or/and cyclic or acyclic ketone peroxide or/and perketal, particularly tert-butyl hydroperoxide (TBHP), cumene hydroperoxide, methylethyl ketone peroxide, in particular cyclic and/or acyclic methylethyl ketone peroxide, acetone peroxide, tert-amyl hydroperoxide (TAHP), di-tert-butyl peroxide (DTBP), tert-butyl peroxybenzoate (TBPB), 1,1-Di-(tert-butylperoxy)-cyclohexane (CH), tetramethyl-dioxa-cyclohexane (TMDOCH), or/and 1,1-bis-(tert-butylperoxy)-3,3,5-trimethylcyclohexane (TMCH), 1,1-bis-(tert-amylperoxy)-cyclohexane, 2,2-di-(tert-butylperoxy)-butane (BH), ethyl-3,3-di-(tert-butylperoxy)-butanoate (EBU) or 4,4-bis-(tert-butylperoxy)-valeric acid-n-butyl ester (NBV) a significant reduction of diesel fuel consumption in diesel engines has been observed.

Preferably, the fuel additive comprises TBHP, DTBP and/or CH.

Most preferably the fuel additive comprises TBHP.

Organic peroxides are thermally unstable compounds, which decompose exothermically with cleavage of the peroxidic oxygen bond. Therefore, for the safe handling or safe transport of organic peroxides they must, for safety considerations often be phlegmatised or are produced industrially already in dilution.

Commercially available peroxide preparations often contain large amounts of water as phlegmatiser, have insufficient thermal or chemical stability or cannot be used commercially as a fuel additive due to the raw materials or production processes used. Preferably, peroxides phlegmatised with water should be avoided as a fuel additive, because water does not mix with the fuel but forms a two-phase system.

Therefore, preferably an anhydrous fuel additive is used. Particularly preferred, the fuel additive of the invention comprises anhydrous TBHP, DTBP and/or CH, even more preferably the fuel additive of the invention comprises anhydrous TBHP, Anhydrous means that the content of water in the fuel additive is <5 wt. %, particularly <1 wt. %, yet more preferably <0.3 wt. %, most preferably <0.01 wt %.

By using anhydrous peroxide, which is miscible with diesel fuel, the formation of an undesirable second aqueous phase can be avoided. The fuel additive, in addition to a peroxide preferably comprises an anhydrous organic solvent. Polar and non-polar solvents can be used. Examples of suitable non-polar solvents are alkanes, in particular aliphatic hydrocarbons such as isododecane, isooctane, decane, nonane and/or n-octane or mixtures of different aliphates. A particularly suitable non-polar solvent is the aliphatic hydrocarbon isododecane. In particular, suitable examples of solvents are diesel and kerosene. Further examples of suitable hydrocarbons are cyclic and acyclic hydrocarbons with 5 to 12, preferably 6 to 10 carbons either saturated or unsaturated. Examples of polar solvents are particularly oxygen-containing solvents, such as, for example, esters and alcohols. Suitable esters used as solvents are in particular phthalates and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB). Alkyl alcohols are preferably used as solvents, particularly C1-C8 alkyl alcohols, more preferably C2-C6 alkyl alcohols, yet more preferably butanol and most preferably tert-butanol (TBA). By using alcohols and particularly tert-butanol, the oxygen content in the fuel additive is increased further, which is desirable.

Preferably the fuel additive comprises a hydroperoxide, dialkylperoxide and/or perketal, particularly TBHP, DTBP and/or CH, and an organic solvent. More preferably, the fuel additive comprises an anhydrous hydroperoxide, an anhydrous dialkylperoxide or/and an anhydrous perketal, particularly anhydrous TBHP, anhydrous DTBP or/and anhydrous CH and an organic solvent.

Particulary preferred is a fuel additive comprising TBHP and an organic solvent, particularly tert-butanol (TBA). Even more preferred is a fuel additive comprising anhydrous TBHP and an organic solvent, particularly tert-butanol (TBA).

According to the invention the additive containing peroxide is added to a diesel fuel. Diesel fuels can comprise, for example, diesel, biodiesel or marine diesel.

Preferably the diesel fuel containing the peroxide-containing diesel additive is anhydrous. Anhydrous means that the diesel fuel containing the peroxide-containing diesel additive has a total content of water of <5 wt. %, particularly <1 wt. %, more preferably <0.3 wt. %, yet more preferably <0.1 wt. %, even more preferably <0.03 wt. %, more preferably <0.01 wt. %, yet even more preferably <0.001 wt. %, most preferably <0.0001 wt. %.

Particularly good results are obtained when the additive containing peroxide is added to a fuel exhibiting a low diesel grade, such as various marine diesel or diesel as used in many non-EU countries.

Low diesel grades or diesel fuels of a low quality have a cetane number without fuel additive of <50, more preferred <45, even more preferred ≤42, yet more preferred ≤40, whereas higher diesel qualities have a cetane number ≥50, more preferred ≥51. Low grade diesel fuels have a minimum cetane number without fuel additive of >20, preferably >25, more preferably >30. The cetane number can be determined according to ASTM-D613, for example.

The cetane number is a characteristic parameter for the combustion quality of diesel fuel. The cetane number is a measure of the ease of ignition or the ignition delay, that is to say the time between the start of fuel injection and the start of combustion. Rapid ignition followed by uniform combustion is advantageous. The higher the cetane number, the shorter the ignition delay and the better the combustion quality.

Now it has been found that the use of a peroxide-containing fuel additive provides a significant reduction of fuel consumption in a diesel engine, when low grade diesel qualities such as commercially available US diesel, are applied. In this respect, peroxides are also suitable e.g. as fuel additives for reducing fuel consumption in regions, where typically low grade diesel fuels are applied.

Preferably the peroxide-containing fuel additive applied according to the invention increases the cetane number of a fuel with fuel additive by at least 2, more preferred by at least 3, yet more preferred by at least 5, most preferred at least by 7 compared to the cetane number of the same fuel without fuel additive.

A diesel fuel admixed with the peroxide-containing additive can be applied in diesel engines such as used in automotives or ships or provided for stationary diesel engines to generate energy. A particularly significant reduction of fuel consumption is effected in low compression diesel engines. Compared to modern diesel engines complying with current Euro 5 standard, low compression diesel engines exhibit a lower compression ratio. Modern high compression diesel engines exhibit a compression ratio of at least 19:1, more preferred at least 21:1. In contrast, low compression diesel engines exhibit a compression ratio of less than 19:1, particularly of less than 18:1 and preferably less than 16:1.

The compression ratio describes the ratio of the total cylinder chamber prior to compression to the remaining space after compression. The compression of the cylinder chamber causes a rise in temperature in the cylinder chamber. A high compression ratio provides easy self-ignition.

Further, the size of displacement per cylinder determines the quality of combustion in a diesel engine. A particularly significant reduction of fuel consumption by addition of a peroxide, particulary TBHP, is discovered in engines with a large displacement per cylinder, particularly for a displacement of at least 1000 cm³, more preferably at least 2000 cm³, yet even more preferably at least 3000 cm³ per cylinder. A large displacement per cylinder effects worse mixing or blending of the fuel with air. Thus, without additive, there is worse or incomplete combustion of the fuel.

Displacement or displaced volume describes the enclosed volume of a cylinder in a combustion engine, which results from the stroke of a single piston and the effective piston cross section. The cylinder displacement hence is the volume displaced by the stroke of the piston in a combustion engine.

The amount of peroxide, particularly TBHP, DTBP or/and CH, more particularly TBHP, in the fuel additive is preferably at least 10 wt. %, more preferably at least 30 wt. %, yet more preferably at least 40 wt. %, most preferably at least 50 wt. %. Pure peroxide is not preferred for safety considerations. However, pure peroxide may also be suitable for the use as fuel additive according to the invention. The amount of peroxide, particularly TBHP, DTBP or/and CH, more particularly TBHP, in the fuel additive is therefore preferably up to 90 wt. %, more preferably up to 75 wt. % and most preferably up to 60 wt. %. The amount of anhydrous organic solvent, particularly alcohols and preferably tert-butanol (TBA), is accordingly at least 10 wt. %, more preferably at least 25 wt % and most preferably at least 40 wt. % and up to 90 wt. %, more preferably up to 70 wt. % and most preferably up to 50 wt. %.

A fuel additive that comprises 30 to 70 wt. % peroxide in 70 to 30 wt. % alcohol has been shown to be particularly suitable and accordingly most preferred. A fuel additive that comprises 20 to 80 wt. % peroxide in 80 to 20 wt. % alcohol has also been shown to be particularly suitable and accordingly more preferred. A fuel additive that comprises 50 to 60 wt. % peroxide in 60 to 50 wt. % alcohol is yet more preferred. A fuel additive that comprises 40 to 60 wt. % peroxide in 60 to 40 wt. % alcohol is even more preferred. A fuel additive that comprises 55 wt. % peroxide and 45 wt. % alcohol is most preferred. Due to the production process, peroxides can be phlegmatised by an oxygen-containing solvent, preferably in an alcohol, particularly in tert-butanol, thereby improving safety during transport and further handling.

A fuel additive that comprises 30 to 70 wt. % TBHP in 70 to 30 wt. % tert-butanol (TBA) has been shown to be particularly preferred. A fuel additive that comprises 50 to 60 wt. % TBHP in 60 to 50 wt. % tert-butanol is yet more preferred. A fuel additive that comprises 40 to 60 wt. % TBHP in 60-40 wt. % tert-butanol is even more preferred. A fuel additive that comprises 55 wt. % TBHP and 45 wt. % tert-butanol is most preferred.

It has been found that a reduction of fuel consumption can be achieved even with small amounts of fuel additive.

The peroxide, particularly TBHP, DTBP or/and CH, more particularly TBHP, is applied in an amount of 0.001 to 10 wt. %, more preferably from 0.01 to 8 wt. %, more preferably from 0.025 to 5 wt. %, yet more preferably from 0.055 to 4 wt. % most preferably from 0.1 to 3 wt. %, and, in particular from 0.1 to 0.5 wt %, based on the total weight of the fuel.

In a preferred embodiment the invention relates to the use of a diesel fuel additive in a diesel fuel for reducing fuel consumption in a diesel engine characterized in that the fuel additive comprises an organic peroxide being applied in an amount from 0.025 to 10 wt. %, in particular from 0.1 to 3 wt. %, based on the total weight of the fuel, even more particularly from 0.1 to 0.5 wt. %.

In another preferred embodiment the invention relates to the use of a diesel fuel additive in a diesel fuel for reducing fuel consumption in a diesel engine characterized in that the fuel additive comprises an anhydrous organic peroxide being applied in an amount from 0.025 to 10 wt %, in particular from 0.1 to 3 wt. %, even more particularly from 0.1 to 0.5 wt. %, based on the total weight of the fuel.

In yet another preferred embodiment the invention relates to the use of a diesel fuel additive in a diesel fuel for reducing fuel consumption in a diesel engine characterized in that the fuel additive comprises an anhydrous organic peroxide being applied in an amount from 0.025 to 10 wt. %, in particular from 0.1 to 3 wt. %, even more particularly from 0.1 to 0.5 wt. %, based on the total weight of the fuel and the diesel fuel has a cetane number of <45 without fuel additive.

In a particular preferred embodiment the invention relates to the use of a diesel fuel additive in a diesel fuel for reducing fuel consumption in a diesel engine characterized in that the fuel additive comprises anhydrous TBHP and TBA. In a further particular preferred embodiment the invention relates to the use of a diesel fuel additive in a diesel fuel for reducing fuel consumption in a diesel engine characterized in that the fuel additive comprises anhydrous DTBP or/and CH.

In another preferred embodiment the invention relates to the use of a diesel fuel additive in a diesel fuel for reducing fuel consumption in a diesel engine characterized in that the fuel additive comprises anhydrous TBHP and TBA, wherein TBHP is applied in an amount from 0.025 to 10 wt. %, in particular from 0.1 to 3 wt. %, even more particularly from 0.1 to 0.5 wt. %, based on the total weight of the fuel.

In yet another preferred embodiment the invention relates to the use of a diesel fuel additive in a diesel fuel for reducing fuel consumption in a diesel engine characterized in that the fuel additive comprises anhydrous TBHP and TBA wherein TBHP is applied in an amount from 0.025 to 10 wt. %, in particular from 0.1 to 3 wt. %, even more particularly from 0.1 to 0.5 wt. %, based on the total weight of the fuel and the diesel fuel has a cetane number of <45 without fuel additive.

It is also possible according to the invention to combine the fuel additive and/or the fuel with other components. Preference is given, for example, to an additive comprising at least two peroxides, particularly selected from hydroperoxides, dialkylperoxides, cyclic or acyclic peroxides and/or perketals. Preference is further given, for example, to an additive comprising at least two peroxides, particularly selected from hydroperoxides, dialkyl peroxides and/or cyclic or acyclic ketone peroxides. Particularly preferred is tert-butyl hydroperoxide (TBHP) in combination with a further peroxide, particularly selected from cumene hydroperoxide, di-tert-butylperoxide (DTBP), methylethyl ketone peroxide, in particular cyclic and acyclic methylethyl ketone peroxide, acetone peroxide, tert-amyl hydroperoxide (TAHP), di-tert-butyl peroxide (DTBP), tert-butyl peroxybenzoate (TBPB), 1,1-Di-(tert-butylperoxy)-cyclohexane (CH), tetramethyl-dioxa-cyclohexane (TMDOCH) or/and 1,1-bis-(tert-butylperoxy)-3,3,5-trimethylcyclohexane (TMCH), 1,1-bis-(tert-amylperoxy)-cyclohexane, 2,2-di-(tert-butylperoxy)-butane (BH), ethyl-3,3-di-(tert-butylperoxy)-butanoate (EBU) or 4,4-bis-(tert-butylperoxy)-valeric acid-n-butyl ester (NBV). Further, an additive is preferred that comprises at least one peroxide and additionally tert-butylalcohol or/and 2-ethylhexylnitrate (2-EHN).

Preferably, reduction of fuel consumption in an engine can be observed by continuously or constantly using the peroxide-containing fuel additive during the entire operation time.

Preferably, reduction in fuel consumption can be observed when the fuel containing the peroxide-containing fuel additive is continuously used in a diesel engine for a runtime or operation time of at least 100 hours, preferred at least 170 hours, more preferred at least 240 hours and most preferred at least 310 hours.

Preferably, reduction in fuel consumption can be observed when the fuel containing the peroxide-containing fuel additive is continuously used in a diesel engine for a runtime or operation time of at least 4 days, preferred at least 7 days, more preferred at least 10 days and most preferred at least 13 days.

It is less preferred, although also possible, that the fuel consumption in an engine can be reduced by adding the fuel containing the peroxide-containing fuel additive in intervals. Thereby it is understood, that certain amounts of fuel with the peroxide-containing fuel additive are added in certain time intervals while using fuel without the peroxide-containing fuel additive otherwise. Preferably, the amount of added fuel with the peroxide-containing fuel additive is at least 10 liters, preferably at least 20 liters, more preferred at least 40 liters and most preferred at least 60 liters. Preferably, the fuel containing the peroxide-containing fuel additive is used for 10 to 1000 hours, preferably 50 to 500 hours, more preferred 100 to 250 hours alternating with using the fuel without the peroxide-containing fuel additive for 10 to 1000 hours, preferably 50 to 500 hours, more preferred 100 to 250 hours.

It was further observed that the use of a peroxide-containing fuel additive provides prevention, reduction or removal of undesired deposits or contaminants in a diesel engine. Undesired deposits in an engine can be formed due to incomplete combustion of the fuel, impurities in the fuel or/and suction of impurities from air. As a result thereof, apart from volatile gases, also finest solids or particles are formed. These particles can deposit inter alia on the fuel injection valves and channels of the engine. Deposits at the injection valves hamper that diesel fuel completely reaches the combustion chamber of the engine. The use of a peroxide-containing diesel additive removes already existing deposits or contaminants and prevents the formation of new deposits or contaminants in the engine.

Examples of deposits or contaminants comprise small particles, soot or/and glycol.

Further, it was observed that the use of a peroxide-containing fuel additive provides a reduction in friction and wear of the diesel engine. Reduction in friction and wear can be achieved when a fuel additive with high lubrication is used. The HFRR (high frequency reciprocating rig) score is a characteristic parameter for the lubrication of a fuel or a fuel additive. The HFRR score can be determined according to ASTM-D6078 and ASTM-D6079, for example. A high HFRR score is determined for a fuel or fuel additive with bad lubrication as for example untreated ultra-low sulfur diesel having a HFRR score of 636. A high HFRR score results in high friction and wear by the fuel or fuel additive compared to a fuel or fuel additive with a low HFRR score. According to the Engine Manufacturers Association the HFRR score has to be desirably below 460.

Preferably, the fuel with peroxide-containing fuel additive has a HFRR score of at most 400, more preferred at most 370 and most preferred at most 330.

Preferably, the peroxide-containing fuel additive applied lowers the HFRR score of a fuel with fuel additive by at least 70, more preferably at least 140 and most preferably at least 210 compared to the same fuel without fuel additive.

Preferably, the peroxide-containing fuel additive applied lowers the HFRR score of a fuel with fuel additive by at least 30, more preferably at least 60 and most preferably at least 90 in comparison to the limit value of Engine Manufacturers Association.

Further, it was observed that the use of a peroxide-containing fuel additive provides a reduced smoke emission together with a cleaner (whiter) smoke emission compared to the emission generated when using untreated fuel. Consequently, the use of a peroxide-containing fuel additive provides a reduction of fuel particulate emission, e.g. soot contaminants.

The particulate matter (PM) mass is a characteristic parameter for regulating the emission of fuel combustion. The mass of PM is determined by well-known sampling methods based on the weight of PM collected on a sampling filter. Preferably, using a fuel with peroxide-containing fuel additive leads to a reduction of PM mass of at least 5%, more preferably of at least 10%, even more preferably of at least 15% compared to the PM mass of an untreated fuel measured under the same sampling conditions.

Also part of this invention is a method for reducing diesel fuel consumption in a diesel engine wherein a fuel additive comprising a peroxide is added to the diesel fuel.

EXAMPLE 1

Reduction of Fuel Consumption with TBHP and TBA as Fuel Additive

To a conventional US base diesel fuel (cetane number=42) was added 0.25 wt. % of a fuel additive consisting of TBHP (55 wt. %) and TBA (45 wt %). The total amount of TBHP added to the diesel fuel is 0.14 wt. %.

By addition of the fuel additive to the above described diesel fuel the cetane number is increased from 42 (without fuel additive) to 48 (with fuel additive).

The test engine used was a Caterpillar D3512-C V12 diesel engine exhibiting a total displacement of 58560 cm³, as well as a displacement per cylinder of 4880 cm³ and a compression ratio of 14.7:1. The test engine was used in a drilling rig.

In a comparative test the consumption of the above mentioned US base diesel fuel was measured without and with diesel fuel additive consisting of TBHP and TBA in the Caterpillar D3512-C diesel engine over a continuous period of time of 22 days. The measurement of fuel consumption of the US base diesel fuel without diesel fuel additive (baseline) is the average of 14 wells tested with the diesel engine. In the period of measurement 1 the fuel additive has been applied for the first time to the diesel engine. Period of measurement 1 is followed by period of measurement 2, which in turn is followed by period of measurement 3. In the period of measurement 2 and 3 the same diesel engine has been used as for period of measurement 1.

In the following table 1 the fuel consumption is indicated as consumption of litres per hour (l/h) as average value for the respective day. FIG. 1 illustrates this result.

TABLE 1 Comparison of the reduction of fuel consumption without and with TBHP and TBA as fuel additive US base Period of Period of Period of diesel measurement 1 measurement 2 measurement 3 fuel without US base diesel US base US base TBHP fuel diesel fuel diesel fuel in TBA with TBHP in with TBHP in with TBHP in (average TBA (average TBA (average TBA (average consumption consumption in consumption in consumption in day in l/h) l/h) l/h) l/h) 1 62.26 67.98 42.96 50 2 72.52 84.82 48.60 53.97 3 75.81 80.51 62.91 52.46 4 80.66 94.25 70.29 43.94 5 92.73 103.52 81.19 54.92 6 99.01 97.77 91.10 66.96 7 106.13 106.36 94.44 73.50 8 114.72 110.64 109.69 82.89 9 114.61 107.15 104.69 84.97 10 116.35 106.28 105.79 88.61 11 116.24 110.26 101.82 90.80 12 119.83 111.13 101.70 96.82 13 120.44 107.80 104.96 98.49 14 117.64 107.42 99.62 96.93 15 121.80 110.26 100.64 101.06 16 120.70 108.36 103.44 101.51 17 121.31 111.24 101.25 101.02 18 122.48 114.12 102.31 100.08 19 123.69 112.72 104.39 102.50 20 123.73 113.59 104.05 101.97 21 124.26 114.31 103.10 103.67 22 122.97 114.38 100.83 101.74 average 108.63 104.31 92.69 84.03

In the course of testing, an increase of fuel consumption was observed for fuel both with and without a fuel additive consisting of TBHP and TBA. Due to the use of the test engine in a drilling rig, the increase of fuel consumption depended on the earth drilled. With longer drilling periods, the drill advanced into deeper and more rigid layers of earth. In order to advance through more rigid layers of earth, the test engine needed more energy, hence consumed more fuel. Although the absolute values of fuel consumption are increasing during drilling, the relative values of fuel consumption of the fuel without fuel additive compared to the fuel with fuel additive are decreasing.

Over the total period of measurement of 22 days an average consumption of 108.63 l/h was yielded for US base diesel fuel without fuel additive and of 104.31 l/h (period of measurement 1), 92.69 l/h (period of measurement 2) and 84.03 l/h (period of measurement 3) was yielded for the same US base diesel fuel with fuel additive. This corresponds to an average fuel saving of 4.32 l or 3.97% (period of measurement 1), 15.94 l or 14.67% (period of measurement 2) and 24.6 l or 22.65% (period of measurement 3) per hour measured.

The increase of fuel consumption during day 1-6 in period of measurement 1 is due to removal of impurities and deposits from the engine. From day 7 in period of measurement 1 on, the engine is cleaned to such an extend that reduction in fuel consumption is observed.

In a longer test over a period of 1306 hours 154662 l US base diesel fuel without fuel additive was consumed and 131684 l US base diesel fuel with fuel additive. This corresponds to a total fuel saving of 22978 l or 14.86%.

EXAMPLE 2

Reduction of Fuel Consumption with TBHP and TBA as Fuel Additive

To a US marine diesel (cetane number=40) was added 0.25 wt. % of a fuel additive consisting of TBHP (55 wt. %) and TBA (45 wt. %). The total amount of TBHP added to this diesel fuel is 0.14 wt. %.

The test engine used was a John Deere 6081 PowerTech 8.1 L, 6 cylinder, marine engine exhibiting a total displacement of 8100 cm³, as well as a displacement per cylinder of 1350 cm³ and a compression ratio of 15.7:1.

In a comparative test the consumption of the above mentioned US marine diesel was measured with and without diesel additive consisting of TBHP and TBA in the John Deere 6081 PowerTech 8.1 L marine diesel engine over a period of time of 25 days. The average consumption of diesel fuel without fuel additive was 25.55 l/h. The average consumption of the diesel fuel with diesel fuel additive was reduced compared to the diesel fuel without fuel additive during the period of measurement 1 (day 11-15) by 2.1%, during the period of measurement 2 (day 16-20) by 8.9% and during the period of measurement 3 (day 21-25) by 17.9%. This test result is illustrated in FIG. 2.

The increase of fuel consumption during day 1-5 and day 6-10 is due to removal of impurities and deposits from the engine which impurities clog the engine filter. Clogged filters have been changed on day 6, 11 and 16. From day 13 on, the engine is cleaned so that reduction in fuel consumption is observed.

EXAMPLE 3

Reduction of Fuel Consumption with TBHP and TBA as Fuel Additive

To a conventional US base diesel fuel (cetane number=42) was added 0.25 wt. % of a fuel additive consisting of TBHP (55 wt. %) and TBA (45 wt. %). The total amount of TBHP added to the diesel fuel is 0.14 wt. %.

In comparative tests the average consumption of the above mentioned base diesel fuel was measured without and with diesel fuel additive consisting of TBHP and TBA in diesel engines of various types of buses. In the following table 2 the average consumption is indicated as consumption in litres per 100 km for various buses.

TABLE 2 Comparison of the reduction of fuel consumption without and with TBHP and TBA as fuel additive in various types of buses. US base diesel fuel US base without diesel fuel total km TBHP in with TBHP travelled reduction TBA in TBA with a US of (average (average base diesel average consumption consumption fuel with consumption Bus in in TBHP in (in No. Bus description l/100 km) L/100 km) TBA %) 1 1995 Amtran 47.47 40.94 676 14 International V 14.5 tons 2 2002 Amtran 97.51 69.73 686 28 International V 14.5 tons 3 2008 Caterpillar I-6 47.00 41.37 3156 12 16.5 tons 4 2008 Caterpillar I-6 44.17 40.80 3125 7.7 16.5 tons 5 2008 Caterpillar I-6 43.20 39.76 3323 8.0 16.5 tons 6 2008 Caterpillar I-6 44.59 40.24 2790 9.8 16.5 tons 7 2008 Caterpillar I-6 44.51 39.97 2771 10 16.5 tons 8 2008 Caterpillar I-6 40.73 28.21 3294 31 16.5 tons 9 2008 Caterpillar I-6 46.35 27.04 3663 42 16.5 tons 10 2009 Mercedes Benz 38.59 35.77 2597 7.3 I-6 16.5 tons 11 2009 Mercedes Benz 40.73 37.72 2294 7.4 I-6 16.5 tons 12 2009 Mercedes Benz 47.19 42.41 3489 10 I-6 16.5 tons 13 2009 Mercedes Benz 46.53 28.38 2246 39 I-6 16.5 tons

EXAMPLE 4

Reduction in Friction by Using TBHP and TBA as a Fuel Additive

To an untreated ultra-low sulfur diesel (cetane number=42) was added 0.25 wt. % of a fuel additive consisting of TBHP (55 wt. %) and TBA (45 wt. %). The total amount of TBHP added to the diesel fuel is 0.14 wt. %.

In comparative tests the HFRR score of the above mentioned untreated ultra-low sulfur diesel was measured without and with different diesel fuel additives. In the following table 3 the HFRR score of untreated ultra-low sulfur diesel is indicated as well as the HFRR score of ultra-low sulfur diesel with different fuel additives. Moreover, the HFRR score of the fuel with fuel additive is compared to the fuel without fuel additive.

TABLE 3 HFRR score of base fuel without as well as with diesel additives HFRR Additive/Fuel score Reduction Standard of the Engine Manufacturers <460 Association (desired) Untreated ultra-low sulfur diesel 636 1 2-EHN (25.3-38.6 wt. %); petroleum 447 189 naphta (27.2-41.3 wt. %) trimethyl- benzene (0.4-1.96 wt. %), naphthalene (3.12 wt. %), 2-ethylhexanol (0.4-1.96 wt. %) 2 2-EHN (10-19.9 wt. %), petroleum 461 175 naphta (60-69 wt. %) trimethylbenzene (20-29 wt %) 3 2-EHN (30-60 wt. %), light aromatic 470 166 petroleum naphta (30-60 wt. %) 1,2,4- trimethylbenzene (10-30 wt. %) 4 1,2,4-trimethylbenzene (30-60 wt. %) 488 148 trimethylbenzene (30-60 wt. %) solvent naphta, heavy aromatic (5-10 wt. %) 5 Distillates petroleum, hydrotreated light 603 33 (30-50 wt. %), 2-EHN (20-30 wt. %), naphta (petroleum), heavy aromatic 10-30 wt. %) 6 TBHP (55 wt. %), TBA (45 wt. %) 316 320

The diesel additive consisting of TBHP and TBA resulted in a reduction of the HFRR score of 320 and is below the standard of the Engine Manufacturers Association.

EXAMPLE 5

Reduction of Fuel Consumption with DTBP, CH or TBHP as Fuel Additive

Tests were performed, wherein to a conventional diesel fuel (cetane number=42) was added 0.25 wt. % of a fuel additive comprising DTBP, CH or TBHP, respectively, whereby in each of the used fuel additive formulations DTBP was present in pure form, CH as a 80% solution in isododecane and TBHP as a 55% solution in TBA. The total amount of DTBP added to the diesel fuel is 0.25 wt. %. The total amount of CH added to the diesel fuel is 0.20 wt. %. The total amount of TBHP added to the diesel fuel is 0.14 wt %.

The diesel generator used in each of the tests was a SDMO 30 kVA generator with a 2.9 l 3-cylinder diesel John Deere motor. The diesel fuel used for testing was Engen Dynamic Diesel 50 ppm. The test engine was used at a temperature range between 25° C. to 31° C.

In a comparative test, the consumption of the above-mentioned diesel fuel was measured without and with diesel fuel additive consisting of DTBP, CH or TBHP. The measurement of fuel consumption (under no load condition) of the US based diesel fuel without diesel fuel additive (base line) was established over a course of seven individual 30-minute runs using 21 of untreated fuel. For testing the fuel additives, the generator fuel system was purged with 21 of fuel treated with the respective fuel additives and the diesel consumption (under no load condition) using the treated fuel was established over a course of seven individual 30-minute runs.

In the following Table 4, the full consumption is indicated as consumption of milliliter as average value for the respective run.

TABLE 4 Pure DTBP CH 50 ppm dosed dosed TBHP dosed Run (30 minutes) Diesel diesel diesel diesel 1 735 630 660 660 2 780 672 648 639 3 690 690 645 639 4 690 711 630 666 5 723 660 645 669 6 744 666 639 651 7 729 687 645 624 Average consumption per 727.29 673.71 644.57 649.71 run (ml) Average consumption per 1454.57 1347.43 1289.14 1299.43 hour (ml) Average diesel consumption 53.57 82.71 77.57 reduction (ml) Percentage reduction 7.37% 11.37% 10.67%

Over the total period of measurement of seven runs, an average consumption per run of 727.29 ml/run was yielded for the diesel fuel without fuel additive. A reduction of average fuel consumption to 673.71 ml/run (DTBP), 644.75 ml/run (CH) and 649.71 ml/run (TBHP) was yielded for the diesel fuel dosed with the respective fuel additives. This corresponds to an average reduction of fuel consumption of 53.57 ml/run and percentage reduction of 7.37% for DTBP dosed fuel additive, and respectively of 82.71 ml/run and 11.37% for CH dosed fuel additive and 77.57 ml/run and 10.67% for TBHP fuel additive for the overall measurement.

These test results indicate that each of the three fuel additives have a significant and immediate impact of reducing diesel consumption when added to a US base diesel fuel.

Moreover, a marked and immediate visual impact of reduced smoke emission and cleaner (whiter) smoke emission could be observed (data not shown) from the generator when using the diesel treated with the fuel additives as opposed to the untreated diesel. 

1.-17. (canceled)
 18. A method for reducing fuel consumption in a diesel engine comprising: adding a fuel additive comprising a peroxide to a diesel fuel; and, permitting a diesel engine to combust the fuel additive and the diesel fuel.
 19. The method of claim 18, wherein the fuel additive comprises at least one organic peroxide.
 20. The method of claim 19, wherein the at least one organic peroxide is a hydroperoxide, dialkylperoxide, a cyclic or acyclic ketone peroxide, a perketal or a combination thereof.
 21. The method of claim 18, wherein the fuel additive comprises tert-butylhydroperoxide (TBHP), cumene hydroperoxide, methylethylketonperoxide, acetone peroxide, tert-amyl hydroperoxide (TAHP), di-tert-butyl peroxide (DTBP), tert-butyl peroxybenzoate (TBPB), 1,1-Di-(tert-butylperoxy)-cyclohexan (CH) or tetramethyl-dioxa-cyclohexane (TMDOCH).
 22. The method of claim 18, wherein the fuel additive comprises TBHP.
 23. The method of claim 18, wherein the fuel additive comprises DTBP.
 24. The method of claim 18, wherein the fuel additive comprises CH.
 25. The method of claim 18, wherein the fuel additive is anhydrous.
 26. The method of claim 25, wherein water in the anhydrous fuel additive is <5 wt. %, <1 wt. %, <0.3 wt. %, or <0.01 wt. %.
 27. The method of claim 18, wherein the fuel additive further comprises a solvent, wherein the solvent is an alcohol or a hydrocarbon.
 28. The method of claim 27, wherein the alcohol is tert-butyl alcohol, and the hydrocarbon is isododecane, diesel, kerosene or 2,2,4-trimethyl-1,3-pentanediol diisobutyrate.
 29. The method of claim 18, wherein the fuel additive comprises a mixture of TBHP and tert-butyl alcohol (TBA).
 30. The method of claim 29, wherein the TBHP is anhydrous TBHP.
 31. The method of claim 18, wherein the diesel fuel without the fuel additive has a cetane number of <50 or <45.
 32. The method of claim 18, wherein the diesel fuel with fuel additive has a cetane number larger by at least 2 compared to the diesel fuel without fuel additive.
 33. The method of claim 18, wherein the diesel engine has a displacement of at least 1000 cm³ per cylinder.
 34. The method of claim 18, wherein the peroxide is in an amount of 0.001 wt. % to 10 wt. %, 0.25 wt. % to 10 wt. %, 0.1 wt. % to 3 wt. % or 0.1 to 0.5 wt. %, based on the total weight of the fuel.
 35. The method of claim 18, wherein the fuel consumption of diesel fuel with fuel additive is reduced by at least 5% compared to the fuel consumption of diesel fuel without fuel additive.
 36. The method of claim 18, wherein the fuel consumption is reduced when the fuel additive is continuously used for an operation time of the diesel engine of at least 100 h.
 37. The method of claim 18, wherein deposits in the diesel engine are prevented, reduced and/or removed.
 38. The method of claim 18, wherein the diesel fuel with the fuel additive has a HFRR score of at least 70 lower than the diesel fuel without the fuel additive. 